The present invention relates to elastomeric flowable gaskets for use with corrugated pipe, and more particularly relates to elastomeric flowable gaskets for sealing the joint between a pair of telescopically engaged sections of corrugated pipe, or sealing the joint between a section of corrugated pipe and a coupling sleeve extending thereover.
In recent years, corrugated plastic tubing has become increasingly popular for use in underground water and sewer drainage systems, particularly plastic corrugated tubing having a large diameter. Such tubing must not only be strong to resist the pressure of the soil surrounding the pipe, but it must also be tightly sealed to prevent soil and other liquids, such as water, from infiltrating the system, and to prevent the sewage or other fluid flowing within the sections of pipe from escaping into the surrounding soil.
In the past, other gaskets and coupling methods have been utilized which have proved to be ineffective, time consuming to assemble and implement, and costly to manufacture. Examples of such prior art are shown in U.S. Pat. No. 4,702,502, issued to Shade et al on Oct. 27, 1987; and U.S. Pat. No. 4,202,568, issued to Strom on May 13, 1980.
In Shade et al '502, a gasket is shown which utilizes relatively thick protrusions that extend substantially into the valleys between adjacent ribs on a piece of corrugated tubing, and are designed to completely fill such valleys and consequently seal between the corrugated tubing and a sleeve extending thereover. One such rib is designated as an anchoring rib and the others perform a sealing function. Consequently, each rib is equally spaced from the adjacent rib in order to individually occupy separate successive valleys of the corrugated tubing. Moreover, the gasket shown in Shade et al '502 must necessarily have a cross-sectional radial dimension which is at least equal to the axial dimensions of one pipe-rib and two (2) valleys of a section of corrugated tubing. Such restrictions in the design thereof require large amounts of material to manufacture same.
As mentioned above, such a gasket as described in Shade et al '502 requires an amount of material sufficient to fill at least two valleys between adjacent ribs of a section of corrugated tubing. With the increasing popularity of the use of corrugated tubing for water and sewer drainage systems, such a gasket as described immediately above has proven to be cost prohibitive due to the large expense for materials. Particularly with the use of large diameter corrugated tubing (usually 8" in diameter or larger), the volume of space occupied by the valleys between adjacent ribs on a section of corrugated pipe becomes large, and consequently the cost of material for producing such a gasket becomes prohibitive.
Similarly, as shown in Strom '568, others in the past have attempted to seal the joint between adjoining sections of corrugated tubing by providing a gasket to overlap the joint, and tightening the seal over the joint through the use of a locking ring. The locking ring securely connects the adjacent sections of corrugated tubing together. Again, the gasket utilized for such a coupling apparatus must be relatively thick and have larger dimensions to cover the joint between adjoining sections of corrugated tubing, thereby increasing the cost of manufacture of same. Moreover, a locking ring must be provided to hold the seal and sections of corrugated tubing securely in place, thereby further increasing the cost of manufacture of same. The assembly of such a sealing system is extremely time consuming and difficult to implement.
The increasing popularity for using corrugated tubing (particularly tubing having a large diameter) for underground water and sewer systems has brought about a strong desire and need in the associated industry for an efficient and cost effective means for sealing such corrugated tubing from external infiltration of soil and liquid, and from the escape of fluids and solids flowing therethrough. The present invention utilizes a minimal amount of incompressible elastomeric flowable material to provide a bidirectional corrugated pipe-rib seal which is markedly less expensive to produce and is unique in its application and structure.
The present invention is designed and constructed to seal against infiltration or the escape of fluids and solids from the corrugated tubing by sealing the joints between the proximal and distal areas of the crest of a rib of a piece of corrugated tubing and the sleeve which extends thereover. By so doing, there is no need to fill the entire volume of the valleys between adjacent ribs of a section of corrugated tubing. Consequently, much less material is used and the cost to manufacture same is markedly reduced.